Can someone please explain how they work/how long it takes for them to show up?

I’m 4 days away from when I should get my period, and I woke up at 6a and took a fr test. It looked negative to me and to my husband at the 3 min mark so I tossed aside and went back to sleep.

I woke up at 820a and went and looked at the first test (which I know I shouldn’t have done) and saw a definite second line. But it was 2.5 hours after the test was taken.

I decided to take a second test and I swear I saw a faint line within 4 mins, and a more obvious one within 10 mins. Could this still be an evap line? I’ve just never heard of indents/Evaps until recently on this app.

If I’m in the wrong group, I’m sorry! I will take down. Please just let me know.